Inductance affects the flow of electrical current in a conductor much
like mechanical inertia affects the rotating mass of a flywheel. Because of its mass, it is hard to get a flywheel to start turning.
However, once turning the flywheel has energy stored in its motion
(kinetic energy). It's hard to start a flywheel turning but once it's
turning it's hard to stop. As discussed previously, it's hard to push
current into an inductor but once the current is flowing it's hard to
stop. The inductor stores energy in its magnetic field.
An inductor resists changes in current. Since alternating current (AC)
is repeatedly changing direction it is effectively blocked by an
inductor. The more often the current changes direction (the frequency)
the more an inductor opposes it. An inductor is said to pass DC but block AC.